test: Enhance Anthropic test coverage with comprehensive validation and edge cases

[alxkm]

Comprehensive test coverage improvements for Anthropic module
Strengthens test suites for both AnthropicRuntimeHints and AnthropicChatOptions with extensive validation scenarios:

AnthropicRuntimeHints improvements:

• Verifies nested API classes (ChatCompletionRequest, AnthropicMessage, ContentBlock) are properly registered
• Ensures hint isolation - only reflection hints registered, no proxy/serialization hints
• Validates package specificity and prevents cross-contamination from other AI modules
• Tests consistency across multiple instances and JSON annotated class detection

AnthropicChatOptions improvements:

• Tests boundary values (Integer.MAX_VALUE, edge floating-point values)
• Validates deep copy behavior with mutable collections to prevent reference sharing
• Comprehensive equals/hashCode testing including null fields and mixed states
• Tests metadata isolation and builder partial configuration scenarios
• Ensures robust handling of various data types in tool context maps

These additions improve reliability, prevent regressions, and ensure robust handling of edge cases in native compilation scenarios and object lifecycle management.

[sobychacko]

Merged via dffec8d